My watercooled P182

eLekTRiK · Post by **eLekTRiK** » Sun Dec 16, 2007 11:43 pm

I finally finished putting together my new rig. The components are a little more power-hungry than a typical silent PC, but I needed the extra cores and overclock for work (saves around 4hrs daily compared to my old 2.4 Northwood), and the video card is fun for occasional gaming. At any rate, I think that this build is interesting because of the unusual setup for the radiators.

From the outside, it looks almost like a stock P182, if you ignore the fillport.

The front view shows some of the case mods, described below.

Here you can see the water cooling gear with most of the system's heat isolated in the bottom chamber.

Components:
Antec P182
Q6600 G0 @ 3.0GHz, stock voltage, C1E+EIST enabled, water-cooled
4GB DDR2 @ 800MHz
Gigabyte P35-DS3L, north bridge water-cooled
8800GT 512MB @700/1700/1000, water-cooled
Antec Phantom 350W fanless PSU
Samsung SP1614C (160GB, 7200rpm) in SmartDrive 2002C
4 x Scythe S-FLEX SFF21E 1200rpm fans
Water Cooling:
CPU/NB/GPU blocks
DB1 pump
2 x 120mm radiators

Cooling and Silence:
In this rig, almost all of the heat is dissipated in the lower chamber, greatly reducing the burden on the upper-chamber exhaust fans, which have a direct path to my ears. Mounting the two radiators and their fans in series in the tunnel probably isn't quite as effective for cooling as using a dual 120mm radiator outside the case, but this approach allows the sound from the radiator fans to be muffled by the walls of the case.

I run both of the upper chamber exhaust fans at ~400rpm, where they are pushing very little air but are effectively inaudible from where I'm sitting. They're set to ramp up if the system temperature gets too hot, but it hasn't been necessary even at full load.

In the tunnel, I soft-mounted the fans to the radiators using some of the silicone grommets from the unused P182 drive cages. The gaps between the radiators and the edges of the case, as well as the gaps between the fans and the radiators, are filled with some cheapo acoustic foam to help the "wind tunnel" by reducing recirculation of exhaust air. Although my experience with the Phantom suggests that it doesn't do very well with zero airflow, the slightly warm exhaust airflow from the radiators is more than sufficient to keep the fanless PSU happy.

The fans in the tunnel will ramp up from an inaudible ~500rpm to ~800rpm at full load, but most stressful tasks like gaming don't even cause the fans to ramp at all. The fans in the tunnel are muted by the case, so even though I can hear them at 800rpm if I listen carefully at night, the slight whoosh isn't really abrasive. All fans are controlled using SpeedFan, with 2 fans connected to each of the two controllable headers on the motherboard.

The SmartDrive enclosure (and the hard drive in it) are leftovers from my previous machine. The drive is fairly quiet to begin with, and the enclosure does a good job of eliminating the remaining noise. I'm just waiting for SSDs to get cheap before my next upgrade.

The pump itself can make a good deal of noise (mostly vibrational) in comparison to some of the other quiet components - which isn't to say that it is loud. I ended up wrapping it in several layers of cheapo acoustic foam and seating it on a multi-layer block of acoustic foam. This got rid of the noise and most of the vibration - unless I put my ear up to the case, I don't hear it.

Case mods:
I had to remove various pieces from the lower chamber to make room for the radiators, and I had to take a dremel to the floor of the main chamber so that I could pass the tubes to the lower chamber without having one of the radiators smack up against the PSU. I added a hole for the fillport at the top of the case, and I trimmed the plastic vents covering the air filters for improved airflow. I snipped the metal behind the filter in the lower chamber since that is where I need the most airflow, but I didn't bother doing the same for the upper chamber. I also added a mesh intake in the unused drive bays to get good airflow over the SmartDrive enclosure. The front door is lined with a thin layer of acoustic foam, mainly to help mute the "whoosh" escaping from the front of the tunnel when the fans are turned up.

Temperatures:
With tunnel fans at ~1200rpm, the warmest core sits at 30C idle, 51C load. At ~500rpm idle / ~800rpm load on the tunnel fans (my day-to-day use settings), the warmest core reaches 42C idle and 60C load, still well within safe operating temperatures. These measurements include a 15C offset in SpeedFan.

lor77 · Post by **lor77** » Mon Dec 17, 2007 9:48 am

Nice innovating ideas with your built.
Nice to see that you only need a 350 watt PSU with a Q core also and video card that you use.
I always thought that watercoolling made extra noise caused mainly by the pump and the extra fans for the radiator.
Would you think that aircooling your rig will make a greater impact at the noise signature?
I guess noise is the question in here.
Nice overall built!

eLekTRiK · Post by **eLekTRiK** » Mon Dec 17, 2007 11:42 am

Nice to see that you only need a 350 watt PSU with a Q core also and video card that you use.

Yeah, my back-of-the-envelope calculations went something like CPU ~ 120W, GPU ~ 110W, other ~ 50W. I think the reason most people go for a bigger PSU than they need these days is because many cheap PSUs can't really handle their rated load.

I always thought that watercoolling made extra noise caused mainly by the pump and the extra fans for the radiator.

The pump can cause extra noise, but if you choose a quiet pump and isolate the vibrations, it can be effectively silent. The airflow required for water cooling should be similar to what you need for air cooling - the total heat that needs to be dissipated is similar in both cases. Instead of having fans on the CPU/GPU heatsinks, there are fans on the radiators. Water-cooling can even be done with large passive radiators and no fans. However, I learned from my last build (2 fans total) that having fewer fans doesn't always mean less noise. For example, even though this new build has 4 fans running, they are all at 400-500rpm where they are quiet enough that I can't hear them. I can hear my wife's Reserator-cooled PC from across the room (Seasonc S12 PSU 120mm fan and 2x120mm case fans) but I can't hear my rig when I am sitting next to it.

Would you think that aircooling your rig will make a greater impact at the noise signature?

With really good heatpipe coolers these days, you can get definitely achieve similar cooling performance to water cooling at lower cost. The problem is that all the heat is dissipated near the components generating the heat and typically exhausted by the exhaust fan(s) at the back of the case. Moving enough air to dissipate that much heat would probably require the exhaust fan to run at 800+ rpm. Even a good fan at the back or top of the case at 1000 rpm would have made too much noise for my liking, as those openings have a direct path to my ears, and it is tricky to dampen that noise without reducing airflow. Water lets you move the heat somewhere else where the noise is easier to deal with.